/*
Adapted from https://github.com/rui314/chibicc

MIT License

Copyright (c) 2019 Rui Ueyama

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/


#include "chibicc.h"

// Encode a given character in UTF-8.
int C_encode_utf8(char *buf, uint32_t c) {
  if (c <= 0x7F) {
    buf[0] = c;
    return 1;
  }

  if (c <= 0x7FF) {
    buf[0] = 0b11000000 | (c >> 6);
    buf[1] = 0b10000000 | (c & 0b00111111);
    return 2;
  }

  if (c <= 0xFFFF) {
    buf[0] = 0b11100000 | (c >> 12);
    buf[1] = 0b10000000 | ((c >> 6) & 0b00111111);
    buf[2] = 0b10000000 | (c & 0b00111111);
    return 3;
  }

  buf[0] = 0b11110000 | (c >> 18);
  buf[1] = 0b10000000 | ((c >> 12) & 0b00111111);
  buf[2] = 0b10000000 | ((c >> 6) & 0b00111111);
  buf[3] = 0b10000000 | (c & 0b00111111);
  return 4;
}

// Read a UTF-8-encoded Unicode code point from a source file.
// We assume that source files are always in UTF-8.
//
// UTF-8 is a variable-width encoding in which one code point is
// encoded in one to four bytes. One byte UTF-8 code points are
// identical to ASCII. Non-ASCII characters are encoded using more
// than one byte.
uint32_t C_decode_utf8(C_Parser *tokenizer, char **new_pos, char *p) {
  if ((unsigned char)*p < 128) {
    *new_pos = p + 1;
    return *p;
  }

  char *start = p;
  int len;
  uint32_t c;

  if ((unsigned char)*p >= 0b11110000) {
    len = 4;
    c = *p & 0b111;
  } else if ((unsigned char)*p >= 0b11100000) {
    len = 3;
    c = *p & 0b1111;
  } else if ((unsigned char)*p >= 0b11000000) {
    len = 2;
    c = *p & 0b11111;
  } else {
	  C_error_at(tokenizer, start, "invalid UTF-8 sequence");
  }

  for (int i = 1; i < len; i++) {
    if ((unsigned char)p[i] >> 6 != 0b10)
	    C_error_at(tokenizer, start, "invalid UTF-8 sequence");
    c = (c << 6) | (p[i] & 0b111111);
  }

  *new_pos = p + len;
  return c;
}

static bool in_range(uint32_t *range, uint32_t c) {
  for (int i = 0; range[i] != -1; i += 2)
    if (range[i] <= c && c <= range[i + 1])
      return true;
  return false;
}

// [https://www.sigbus.info/n1570#D] C11 allows not only ASCII but
// some multibyte characters in certan Unicode ranges to be used in an
// identifier.
//
// This function returns true if a given character is acceptable as
// the first character of an identifier.
//
// For example, ¾ (U+00BE) is a valid identifier because characters in
// 0x00BE-0x00C0 are allowed, while neither ⟘ (U+27D8) nor '　'
// (U+3000, full-width space) are allowed because they are out of range.
bool C_is_ident1(uint32_t c) {
  static uint32_t range[] = {
    '_', '_', 'a', 'z', 'A', 'Z', '$', '$',
    0x00A8, 0x00A8, 0x00AA, 0x00AA, 0x00AD, 0x00AD, 0x00AF, 0x00AF,
    0x00B2, 0x00B5, 0x00B7, 0x00BA, 0x00BC, 0x00BE, 0x00C0, 0x00D6,
    0x00D8, 0x00F6, 0x00F8, 0x00FF, 0x0100, 0x02FF, 0x0370, 0x167F,
    0x1681, 0x180D, 0x180F, 0x1DBF, 0x1E00, 0x1FFF, 0x200B, 0x200D,
    0x202A, 0x202E, 0x203F, 0x2040, 0x2054, 0x2054, 0x2060, 0x206F,
    0x2070, 0x20CF, 0x2100, 0x218F, 0x2460, 0x24FF, 0x2776, 0x2793,
    0x2C00, 0x2DFF, 0x2E80, 0x2FFF, 0x3004, 0x3007, 0x3021, 0x302F,
    0x3031, 0x303F, 0x3040, 0xD7FF, 0xF900, 0xFD3D, 0xFD40, 0xFDCF,
    0xFDF0, 0xFE1F, 0xFE30, 0xFE44, 0xFE47, 0xFFFD,
    0x10000, 0x1FFFD, 0x20000, 0x2FFFD, 0x30000, 0x3FFFD, 0x40000, 0x4FFFD,
    0x50000, 0x5FFFD, 0x60000, 0x6FFFD, 0x70000, 0x7FFFD, 0x80000, 0x8FFFD,
    0x90000, 0x9FFFD, 0xA0000, 0xAFFFD, 0xB0000, 0xBFFFD, 0xC0000, 0xCFFFD,
    0xD0000, 0xDFFFD, 0xE0000, 0xEFFFD, -1,
  };

  return in_range(range, c);
}

// Returns true if a given character is acceptable as a non-first
// character of an identifier.
bool C_is_ident2(uint32_t c) {
  static uint32_t range[] = {
    '0', '9', '$', '$', 0x0300, 0x036F, 0x1DC0, 0x1DFF, 0x20D0, 0x20FF,
    0xFE20, 0xFE2F, -1,
  };

  return C_is_ident1(c) || in_range(range, c);
}

// Returns the number of columns needed to display a given
// character in a fixed-width font.
//
// Based on https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
static int char_width(uint32_t c) {
  static uint32_t range1[] = {
    0x0000, 0x001F, 0x007f, 0x00a0, 0x0300, 0x036F, 0x0483, 0x0486,
    0x0488, 0x0489, 0x0591, 0x05BD, 0x05BF, 0x05BF, 0x05C1, 0x05C2,
    0x05C4, 0x05C5, 0x05C7, 0x05C7, 0x0600, 0x0603, 0x0610, 0x0615,
    0x064B, 0x065E, 0x0670, 0x0670, 0x06D6, 0x06E4, 0x06E7, 0x06E8,
    0x06EA, 0x06ED, 0x070F, 0x070F, 0x0711, 0x0711, 0x0730, 0x074A,
    0x07A6, 0x07B0, 0x07EB, 0x07F3, 0x0901, 0x0902, 0x093C, 0x093C,
    0x0941, 0x0948, 0x094D, 0x094D, 0x0951, 0x0954, 0x0962, 0x0963,
    0x0981, 0x0981, 0x09BC, 0x09BC, 0x09C1, 0x09C4, 0x09CD, 0x09CD,
    0x09E2, 0x09E3, 0x0A01, 0x0A02, 0x0A3C, 0x0A3C, 0x0A41, 0x0A42,
    0x0A47, 0x0A48, 0x0A4B, 0x0A4D, 0x0A70, 0x0A71, 0x0A81, 0x0A82,
    0x0ABC, 0x0ABC, 0x0AC1, 0x0AC5, 0x0AC7, 0x0AC8, 0x0ACD, 0x0ACD,
    0x0AE2, 0x0AE3, 0x0B01, 0x0B01, 0x0B3C, 0x0B3C, 0x0B3F, 0x0B3F,
    0x0B41, 0x0B43, 0x0B4D, 0x0B4D, 0x0B56, 0x0B56, 0x0B82, 0x0B82,
    0x0BC0, 0x0BC0, 0x0BCD, 0x0BCD, 0x0C3E, 0x0C40, 0x0C46, 0x0C48,
    0x0C4A, 0x0C4D, 0x0C55, 0x0C56, 0x0CBC, 0x0CBC, 0x0CBF, 0x0CBF,
    0x0CC6, 0x0CC6, 0x0CCC, 0x0CCD, 0x0CE2, 0x0CE3, 0x0D41, 0x0D43,
    0x0D4D, 0x0D4D, 0x0DCA, 0x0DCA, 0x0DD2, 0x0DD4, 0x0DD6, 0x0DD6,
    0x0E31, 0x0E31, 0x0E34, 0x0E3A, 0x0E47, 0x0E4E, 0x0EB1, 0x0EB1,
    0x0EB4, 0x0EB9, 0x0EBB, 0x0EBC, 0x0EC8, 0x0ECD, 0x0F18, 0x0F19,
    0x0F35, 0x0F35, 0x0F37, 0x0F37, 0x0F39, 0x0F39, 0x0F71, 0x0F7E,
    0x0F80, 0x0F84, 0x0F86, 0x0F87, 0x0F90, 0x0F97, 0x0F99, 0x0FBC,
    0x0FC6, 0x0FC6, 0x102D, 0x1030, 0x1032, 0x1032, 0x1036, 0x1037,
    0x1039, 0x1039, 0x1058, 0x1059, 0x1160, 0x11FF, 0x135F, 0x135F,
    0x1712, 0x1714, 0x1732, 0x1734, 0x1752, 0x1753, 0x1772, 0x1773,
    0x17B4, 0x17B5, 0x17B7, 0x17BD, 0x17C6, 0x17C6, 0x17C9, 0x17D3,
    0x17DD, 0x17DD, 0x180B, 0x180D, 0x18A9, 0x18A9, 0x1920, 0x1922,
    0x1927, 0x1928, 0x1932, 0x1932, 0x1939, 0x193B, 0x1A17, 0x1A18,
    0x1B00, 0x1B03, 0x1B34, 0x1B34, 0x1B36, 0x1B3A, 0x1B3C, 0x1B3C,
    0x1B42, 0x1B42, 0x1B6B, 0x1B73, 0x1DC0, 0x1DCA, 0x1DFE, 0x1DFF,
    0x200B, 0x200F, 0x202A, 0x202E, 0x2060, 0x2063, 0x206A, 0x206F,
    0x20D0, 0x20EF, 0x302A, 0x302F, 0x3099, 0x309A, 0xA806, 0xA806,
    0xA80B, 0xA80B, 0xA825, 0xA826, 0xFB1E, 0xFB1E, 0xFE00, 0xFE0F,
    0xFE20, 0xFE23, 0xFEFF, 0xFEFF, 0xFFF9, 0xFFFB, 0x10A01, 0x10A03,
    0x10A05, 0x10A06, 0x10A0C, 0x10A0F, 0x10A38, 0x10A3A, 0x10A3F, 0x10A3F,
    0x1D167, 0x1D169, 0x1D173, 0x1D182, 0x1D185, 0x1D18B, 0x1D1AA, 0x1D1AD,
    0x1D242, 0x1D244, 0xE0001, 0xE0001, 0xE0020, 0xE007F, 0xE0100, 0xE01EF,
    -1,
  };

  if (in_range(range1, c))
    return 0;

  static uint32_t range2[] = {
    0x1100, 0x115F, 0x2329, 0x2329, 0x232A, 0x232A, 0x2E80, 0x303E,
    0x3040, 0xA4CF, 0xAC00, 0xD7A3, 0xF900, 0xFAFF, 0xFE10, 0xFE19,
    0xFE30, 0xFE6F, 0xFF00, 0xFF60, 0xFFE0, 0xFFE6, 0x1F000, 0x1F644,
    0x20000, 0x2FFFD, 0x30000, 0x3FFFD, -1,
  };

  if (in_range(range2, c))
    return 2;
  return 1;
}

// Returns the number of columns needed to display a given
// string in a fixed-width font.
int C_display_width(C_Parser *tokenizer, char *p, int len) {
  char *start = p;
  int w = 0;
  while (p - start < len) {
    uint32_t c = C_decode_utf8(tokenizer, &p, p);
    w += char_width(c);
  }
  return w;
}
